Low power and Lossy Networks (LLNs), e.g., sensor networks, have a myriad of applications, such as Smart Grid and Smart Cities. Various challenges are presented with LLNs, such as lossy links, low bandwidth, battery operation, low memory and/or processing capability, etc. Shared-media communication networks, such as wireless networks or power-line communication (PLC) networks (a type of communication over power-lines), provide an enabling technology for networking communication. These technologies can be used, for example, in advanced metering infrastructure (AMI) networks, and are also useful within homes and buildings.
Security is an important aspect of many shared-media networks, particularly for LLN solutions, which generally operate over a large physical area in an uncontrolled environment. Existing security protocols typically use a replay counter to ensure freshness of a message and prevent replay attacks. A replay counter is strictly monotonic. The message source must increase the replay counter for each new message. The message destination only accepts messages that have a larger replay counter than that of messages it has previously received. Current replay counter solutions, however, are not well-suited for constrained networks, such as LLNs, where devices are often limited in terms of communication bandwidth, processing capability, and/or memory/storage.